According to the prior art, two parallel plates can be connected by a fixedly connecting component. The fixedly connecting component usually operates by screwing and comprises a screw and a sleeve. One end of the screw has a driven portion that comes with a drive. The other end of the screw has a threaded portion connected to the driven portion. The sleeve fits around the threaded portion of the screw so that the screw can move within the sleeve. Therefore, the fixedly connecting component operates in a manner described below. One end of the sleeve gets coupled to a first object (such as a circuit board), whereas the threaded portion of the screw penetrates one end of the sleeve and corresponds in position to a locking hole of a second object (such as a chassis or a casing), and then a tool exerts a rotational force on the drive of the driven portion of the screw to fasten the threaded portion to the locking hole of the second object, thereby connecting the parallel first and second objects.
However, the fixedly connecting component fails to connect, screw together, or engage two objects which are perpendicular to each other, for example, in the situation where the first object is fixed in place on a plane which extends in direction X, whereas the second object is fixed in place on a plane which extends in direction Y, wherein direction Y is perpendicular to direction X. Therefore, it is important to provide a positioning-engaging device for connecting two objects which are perpendicular to each other and enabling the two objects to be quickly connected and separated by pressing, engagement or twisting without a tool.